add riscv64 architecture support

Author: Alex Suykov <alex.suykov@gmail.com>
Author: Aric Belsito <lluixhi@gmail.com>
Author: Drew DeVault <sir@cmpwn.com>
Author: Michael Clark <mjc@sifive.com>
Author: Michael Forney <mforney@mforney.org>
Author: Stefan O'Rear <sorear2@gmail.com>

This port has involved the work of many people over several years. I
have tried to ensure that everyone with substantial contributions has
been credited above; if any omissions are found they will be noted
later in an update to the authors/contributors list in the COPYRIGHT
file.

The version committed here comes from the riscv/riscv-musl repo's
commit 3fe7e2c75df78eef42dcdc352a55757729f451e2, with minor changes by
me for issues found during final review:

- a_ll/a_sc atomics are removed (according to the ISA spec, lr/sc
  are not safe to use in separate inline asm fragments)

- a_cas[_p] is fixed to be a memory barrier

- the call from the _start assembly into the C part of crt1/ldso is
  changed to allow for the possibility that the linker does not place
  them nearby each other.

- DTP_OFFSET is defined correctly so that local-dynamic TLS works

- reloc.h LDSO_ARCH logic is simplified and made explicit.

- unused, non-functional crti/n asm files are removed.

- an empty .sdata section is added to crt1 so that the
  __global_pointer reference is resolvable.

- indentation style errors in some asm files are fixed.

1 files changed, 29 insertions, 0 deletions

diff --git a/arch/riscv64/bits/alltypes.h.in b/arch/riscv64/bits/alltypes.h.in
new file mode 100644
index 00000000..ae9ba41d
--- /dev/null
+++ b/arch/riscv64/bits/alltypes.h.in
@@ -0,0 +1,29 @@
+#define _Addr long
+#define _Int64 long
+#define _Reg long
+
+TYPEDEF __builtin_va_list va_list;
+TYPEDEF __builtin_va_list __isoc_va_list;
+
+#ifndef __cplusplus
+TYPEDEF int wchar_t;
+#endif
+
+TYPEDEF int blksize_t;
+TYPEDEF unsigned int nlink_t;
+
+TYPEDEF float float_t;
+TYPEDEF double double_t;
+
+TYPEDEF struct { long long __ll; long double __ld; } max_align_t;
+
+TYPEDEF long time_t;
+TYPEDEF long suseconds_t;
+
+TYPEDEF struct { union { int __i[14]; volatile int __vi[14]; unsigned long __s[7]; } __u; } pthread_attr_t;
+TYPEDEF struct { union { int __i[10]; volatile int __vi[10]; volatile void *volatile __p[5]; } __u; } pthread_mutex_t;
+TYPEDEF struct { union { int __i[10]; volatile int __vi[10]; volatile void *volatile __p[5]; } __u; } mtx_t;
+TYPEDEF struct { union { int __i[12]; volatile int __vi[12]; void *__p[6]; } __u; } pthread_cond_t;
+TYPEDEF struct { union { int __i[12]; volatile int __vi[12]; void *__p[6]; } __u; } cnd_t;
+TYPEDEF struct { union { int __i[14]; volatile int __vi[14]; void *__p[7]; } __u; } pthread_rwlock_t;
+TYPEDEF struct { union { int __i[8]; volatile int __vi[8]; void *__p[4]; } __u; } pthread_barrier_t;